Research/Sitter/MAGNDATA / 1.1.22_Sr3Fe2O7.mcif

Sr₃Fe₂O₇

MAGNDATA entry 1.1.22 · source

incommensurate spiral

Incommensurate: the magnetic pattern repeats every so many cells, but not a whole number of them, so it never lines up with the crystal lattice. Here it's a spiral: the spin direction rotates as you move along.

ordered ≤ 115 K (−158 °C)Colour: where that sits relative to 25 °C. Saturation: how much margin it has.

Structure · 11 properties

Magnetic group	X2221′(α,α,0)s00s
Point group	2221′
Parent space group	I 4/m m m No. 139
Repeats every	7.06 cells along a (not a whole number: that's what incommensurate means)
Propagation	[0.1416 0.1416 0] 1k
Cell	a 3.846 · b 3.846 · c 20.234 Å · α 90° · β 90° · γ 90°
Transition	115 K (−158 °C)
Measured at	2 K
Magnetic ions	Fe
Largest moment component	3.19 μ_B
Method	NPD

Symmetry

Stereogram of the magnetic point group: each operation applied to one direction. Filled = upper hemisphere, ring = lower; red operations include time reversal. Lines are mirrors; polygons are 2/3/4/6-fold axes; the centre ring is inversion.

Every structure in X2221′(α,α,0)s00s →

Atom sites · 7 sites · CSV

site	element	x	y	z
Sr1	Sr	0	0	0.5
Sr2	Sr	0	0	0.317
Fe1	Fe	0	0	0.0972
O1_1	O	0	0.5	0.0948
O1_2	O	0.5	0	0.0948
O2	O	0	0	0.1933
O3	O	0	0	0

Incommensurate: the moments are modulated; the picture evaluates each atom's Fourier series at its own phase.

Moment components are along the crystal axes a, b, c (μ_B), as magCIF writes them. Symmetry generates the rest of the cell from these sites.

Source

J.-H. Kim et al. PHYSICAL REVIEW LETTERS (2014) · doi:10.1103/PhysRevLett.113.147206

Cite the original paper and MAGNDATA, not this mirror.

Original file

⬇ 1.1.22_Sr3Fe2O7.mcif from MAGNDATA · entry page

sha256 of this copy: f8dd902d4199f8660b50f46996e7d2715d3b3d0d61a074f0064e24d2718bb782
The mirror keeps the bytes Bilbao served, so the original should hash the same unless MAGNDATA has revised the entry since: shasum -a 256 1.1.22_Sr3Fe2O7.mcif.